Mixed donor ligands, especially P,N ligands, form a class of not too strongly binding ligands that contain a combination of hard and soft donor atoms in a molecule and consequently the resulting metal complexes exhibit unique reactivity. The utility of the P,N ligands has been demonstrated in a whole range of asymmetric catalysis reactions, such as asymmetric allylic alkylation, hydrogenation, transfer hydrogenation, hydrosilylation, hydroboration, hydroformylation, Diels-Alder reaction, Grignard cross-coupling reaction, Heck reaction and conjugate-addition reaction, as well as in copolymerisation, terpolymerisation, catalytic amination and cross-coupling (for references see F. Y. Kwong, K. S. Chan, Organometallics 20, 2570–2578 (2001), and G. Helmchen, A. Pfaltz, Acc. Chem. Res. 33, 336 (2000)).
It has been found that a critical factor for selectivity in enantioselective catalyses with P,N ligands is the “bite angle” P-M-N (coordination angle between M, which is the complexed metal, and the ligand atoms phosphorus and nitrogen). Phosphinoaryloxazoline ligands (PHOX ligands) are known (see G. Helmchen, A. Pfaltz, Acc. Chem. Res. 33, 336 (2000)).
The aim of the present invention is the provision of a new class of ligands which, by virtue of their specific binding angle and the possibility of varying the electron donor properties, enable especially advantageous catalysts to be prepared. A particular objective inter alia is to achieve a higher enantiomeric excess (ee) in the catalysis and to obtain high yields.